Skin stiffness characteristics and loft control production system and method with variable moisture content in input fiberglass media

ABSTRACT

A heating system is provided having a plurality of heated zones, with at least a first zone and a second zone. The first zone receives variable input moisture fiberglass over a first conveyor system and comprises a first compression system above the first conveyor system. Each zone has a fire box at the top and an exhaust stack. Heated air is up drafted through the bottom of the first zone, where the heated air flows from the bottom through the conveyor belt, through the fiberglass media, through the tensioned compression chain, and out the exhaust stack of the first zone. The first zone establishes fiberglass loft, with the second zone providing cure of the fiberglass.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Patent App. No. 62/177,926,filed Mar. 27, 2015, and the foregoing application is incorporated byreference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to improvements to the Modigliani process(U.S. Pat. Nos. 2,081,060; 2,546,230; and 2,913,037) as a system, methodand apparatus for control of skin stiffness characteristics on thesurface of fiberglass filtration media and controlled loft productionwith variable input moisture content. The Modigliani patents providevery few details on how curing is accomplished. Moisture variabilityproblems are with unexpanded fiberglass mat entering the heatingapparatus, not the moisture of the finished fiberglass media.

BACKGROUND

During the production of fiberglass, moisture content of uncured mediaentering the curing process, skin firmness characteristics of curedmedia and finished product uniformity are difficult to control.Additionally, the production of fiberglass has required multipleadditives to control loft and stiffness but these additives causeproblems in processing that must be adjusted by formulation orprocessing changes. Purchasers of fiberglass media cite problems causedby small deviations in loft, skin characteristics and uniformity ofmedia.

Current methods utilize many catalysts, buffers, and miscellaneousadditives to adjust pH, viscosity etc. of resin binder to achieve betterquality fiberglass. Curing methods today tend to be intolerant ofvariability in uncured unexpanded fiberglass mat moisture content.Current methods or apparatuses cannot consistently produce stiffer, welldefined skin characteristics. Most systems and methods today do not useup-drafting of hot curing air to prevent clogging in the exhaust and toprovide cleaner belts in the apparatus.

Additionally, other methods of making fiberglass such as insulationfiberglass use spinneret devices where molten glass is dumped into aspinning pot with holes in the sides. As the glass strands exit thesides by centrifugal force, they are blasted with compressed air whichcuts the fiberglass strands into short lengths. These spinnerets movefrom side to side over a moving conveyor to get them distributed in aneven layer before entering curing ovens. In some cases the ovens utilizeupdraft, some cases downdraft and in other cases both updraft anddowndraft are utilized. This disclosure relates to continuous strandfilament fiberglass, not short lengths as is used in insulation.

It would be advantageous to provide a method regulating moisture.

It would also be advantageous to provide a method that can tolerate moremoisture variations in uncured unexpanded fiberglass mat entering theheating apparatus.

It would further be advantageous to provide a system and method that canconsistently produce the desired skin firmness and thicknesscharacteristics.

It would further be advantageous to provide a method of heating amulti-zoned system at specified temperatures utilizing an updrafttechnique.

It would still further be advantageous to provide a method of creatinggreater loft consistency.

Thus, there remains a considerable need for systems, methods and devicesthat control skin stiffness characteristics on the surface of fiberglassfiltration media providing controlled loft production with variableinput moisture content.

SUMMARY

The present disclosure provides a heating apparatus for curing inputfiberglass with variable moisture content where such heating apparatusadjusts fiberglass loft and provides better controlled skincharacteristics. In the preferred embodiment, the heating apparatus hasa plurality of heated zones of varying lengths not less than fifteenfeet in any zone. A first heated zone operates at a temperature range ofthree hundred degrees Fahrenheit (300° F.) to five hundred degreesFahrenheit (500° F.), and a second heated zone operates at a temperatureof two hundred and seventy-five degrees Fahrenheit (275° F.) to fivehundred degrees Fahrenheit (500° F.). The second heated zone operates onits low temperature range end at least twenty-five degrees cooler thanthe first heated zone. Integrated tensioner mechanisms (tensioner systemand tensioner belts and chain) control tension on the lower conveyorchain and the upper compression conveyor belt. The first heated zone hasa tensioned compression system for the fiberglass media with the secondheated zone available for additional curing. The first heated zonereceives conveyed fiberglass media under an upper compression conveyorbelt. The upper compression conveyor belt is attached to lateral supportdevices, preventing downward deflection of the belt across the width ofthe fiberglass media. The lateral support devices are attached at eachend to a roller chain with rollers riding in a support track. The uppercompression conveyor belt is constructed of a wire mesh allowing air toflow through the belt. The upper compression conveyor belt assemblymounts in the frame which may be raised and lowered by utilizingsynchronized lifting jacks. In the preferred embodiment, the movement ofthe upper compression conveyor belt to change loft could be shorter than3 seconds up to a maximum of 20 seconds for fiberglass loft changingfrom ¼ inch loft to 5 inch loft. Temperature sensors near the surface ofthe fiberglass media in each of the heated zones are used toautomatically control gas valves in each firebox to maintain a constanttemperature. An alternating current (AC) inverter in a closed-loopsystem synchronizes the speeds of the upper compression conveyor belt tothat of a post oven accumulator and a post oven wind-up assembly. Boththe post oven accumulator and the post oven wind-up assembly furthersynchronize with the speed of the lower conveyor chain which precludesabrading of the surface of the media and controls tension on the media,further improving the surface of the fiberglass media. Each heated zonehas a fire box, a blower and a separate exhaust stack positioned at thetopmost section of the heated zone. Heated air is blown downward fromthe firebox and the blower through a ducting system that conveys airdownward around the exterior of the oven to a first heated zonedistribution duct below the fiberglass media. Heated air exits thedistribution duct through a series of openings causing heated air toflow upward. The benefit of updraft is when secondary backers (e.g.scrim or high-loft polyester) are added to the bottom of the fiberglassmat before entry into the oven, the updraft helps bond the secondarylayer to the media.

Heated air is collected above the media through adjustable holes in areturn air plenum at the topmost part of the first heated zone. Theheated air returns to the firebox and blower assembly in a way that apercentage of recirculating air from the plenum can be controlled, andair exhausts out an exhaust stack in the first heated zone and anexhaust stack in a second heated zone.

Loft may also be controlled through the use of a lift mechanism (e.g.,lifting jacks) which adjusts and moves the upper compression conveyorbelt either up or down automatically. In the preferred embodiment, thismovement of the upper compression conveyor belt to change loft istypically 3 seconds, but could be a maximum of 20 seconds if thefiberglass loft changes from ¼ inch loft to 5 inch loft, all at once.All zones are independently heated to different temperatures, with thefirst zone having a temperature range of 300 degrees Fahrenheit to 500degrees Fahrenheit, dependent on the curing requirement of the specificfiberglass product being processed.

BRIEF DESCRIPTION OF THE DRAWINGS

A complete understanding of the present disclosure may be obtained byreference to the accompanying drawings, when considered in conjunctionwith the subsequent, detailed description, in which:

FIG. 1 shows a side view of a transport system for the first zone of aheating apparatus and depicts an upper compression conveyor belt 10, anupper compression conveyor belt drive sprocket 18, and rollers 14supporting lower conveyor chain 16;

FIG. 2 shows a side view of a tension control for a first zone of aheating apparatus and depicts an upper compression conveyor belttensioner 20 and a lower conveyor chain tensioner 22;

FIG. 3 shows a side view of an airflow control for a first zone of aheating apparatus and depicts a firebox and blower 30, hot airdistribution duct 32, return air plenum 34, return air recyclingdirection of air flow 36, fume hood 38, return air plenum and fume hoodexhaust stack 40, and make up air intake 42;

FIG. 4 shows an end view of an airflow control for a first zone of aheating apparatus and depicts a burner and firebox assembly 50, downdraft ducts 52 with direction of airflow indicated away from the burner,direction of airflow updraft through fiberglass media 54, and directionof airflow from return air plenum to recycling 56;

FIG. 5 shows a top view of a first zone of a heating apparatus anddepicts upper compression conveyor belt lifting jacks 60 for loftcontrol;

FIG. 6 shows a side view of a second zone of a heating apparatus anddepicts a firebox and blower 70, hot air supply distribution duct 72,return air plenum 74, return air exhaust stack 76, make up air intake78, and the direction of travel 79 of the fiberglass media, with avertical dashed line indicating the boundary with the first zone and;

FIG. 7 shows a top view of an upper compression conveyor belt rollerchain 80 and 3 inch by 3 inch support track 82;

FIG. 8 shows an end view of upper compression conveyor belt lateralsupport devices 90; and

FIG. 9 shows a front view of outboard bearings 100 and insulation board110.

For purposes of clarity and brevity, like elements and components willbear the same designations and numbering throughout the figures.

DETAILED DESCRIPTION

Disclosed is a heating apparatus for curing fiberglass having anextended length dual curing heating system with at least a fifteen footfirst heated zone and at least a fifteen foot second heated zone.Neither the first heated zone nor the second heated zone has a maximumlength of more than one hundred feet each. The first heated zoneoperates at a temperature range of three hundred degrees Fahrenheit(300° F.) to five hundred degrees Fahrenheit (500° F.) with the secondheated zone operating at a temperature of two hundred and seventy-fivedegrees Fahrenheit (275° F.) to five hundred degrees Fahrenheit (500°F.). The second heated zone operates on the low temperature range end atleast twenty-five degrees Fahrenheit (25° F.) cooler than the firstheated zone.

With reference to FIGS. 1 and 2, integrated tensioner mechanisms (uppercompression conveyor belt tensioner 20, lower conveyor chain tensioner22, and upper compression conveyor belt drive sprocket 18) controltension on the lower conveyor chain 16 and the upper compressionconveyor belt 10 with rollers 14 supporting the lower conveyor chain 16.The first heated zone has an upper tensioned compression system havingan upper compression conveyor belt tensioner 20 and a lower conveyorchain tensioner 22 for the fiberglass media 12. The first heated zonereceives conveyed fiberglass media over a first conveyor belt. An uppercompression conveyor belt 10 is mounted to lateral support devices 90(shown in FIG. 8), which are mounted perpendicular to the direction oftravel of fiberglass media 12, thereby preventing downward deflection ofthe belt across the width of the fiberglass media 12. Lateral supportdevices 90 are attached at each end to an upper compression conveyorbelt roller chain 80 (shown in FIG. 7) with rollers 14 riding in asupport track 82 (shown in FIG. 7).

The upper conveyor compression belt 10 is composed of a wire mesh whichallows air to flow through the belt. The upper compression conveyor belt10 mounts in a support track 82 which can be raised and lowered bysynchronized lifting jacks 60 (shown in FIG. 5). Temperature sensorsnear the surface of the fiberglass media in each of the first heatedzone and the second heated zone are used to automatically control gasvalves in each burner and firebox assembly 50 (shown in FIG. 4) tomaintain a constant temperature. FIG. 3 depicts the position 44 of atemperature sensor. An alternating current (AC) inverter in aclosed-loop system synchronizes the speeds of the upper compressionconveyor belt 10, the post oven accumulator and the post oven wind-upassembly along with the speed of the lower conveyor chain 16, whichprecludes abrading of the surface of the fiberglass media 12 whilefurther controlling tension on the fiberglass media 12.

Each heated zone has a fire box. There is a blower 30 for the firstheated zone (shown in FIG. 3) and a blower 70 for the second heated zone(shown in FIG. 6), along with a separate exhaust stack at the top mostsection of each heated zone. The first heated zone also comprises airplenum and fume hood exhaust stack 40, and the second heated zonecomprises return air exhaust stack 76.

The heated air is then collected above the media 12 through adjustableholes in plenum 34 at the topmost part of the first heated zone. There,return air in the plenum 34 can be returned to the firebox and blower 30or exhausted out the first heated zone return air plenum and fume hoodexhaust stack 40 in a way that recirculating air percentages can becontrolled through make up air intake 42.

With reference to FIG. 5, the loft of the product is controlled throughlifting jacks 60 which adjust and move the upper compression conveyorbelt 10 either up or down automatically. The movement of the uppercompression belt to change loft is typically 3 seconds, but could bealmost instantaneously or up to a maximum of 20 seconds when changes aremade from ¼ inch loft to 5 inch loft all at once, which is quicklyenough such that no media 12 is ruined.

Also disclosed herein is an apparatus with a plurality of heated zoneswith a minimum of at least two heating zones. A first zone is heated toa temperature range of at least three hundred degrees Fahrenheit (300°F.) to no more than five hundred degrees Fahrenheit (500° F.). The firstheated zone has a firebox and blower 30 disposed at the topmost sectionof the first zone, with an air intake 42 and a return air plenum 34,with the return air recycling direction of air flow 36 (as indicated inFIG. 3). Additionally, the topmost section of the first heated zone hasa return air plenum exhaust coupled with a fume hood exhaust stack 40and a fume hood 38 situated exterior to the heating apparatus) disposedjust above upper compression conveyor belt tensioner 20 which isdisposed above lower conveyor chain tensioner 22.

In FIG. 4, the air flow and position of the ductwork are indicatedrelative to the firebox assembly 50 with direction of hot air travel indowndraft duct 52. The air is delivered at the bottom most area of theoven with direction of updraft of the hot air through the media 54 andflow of air from return air plenum to recycling 56. The ductwork isconnected thereto with ducting conducting heated air from a blower andfirebox through ducting disposed along the exterior wall of a first zoneto a bottom most portion of the first zone. The heated air exits theductwork through a series of rectangular slots under lower conveyorchain 16 presenting heated air with an upward flow through lowerconveyor chain 16. The heated air then flows upward through a firstsurface of a fiberglass media through the fiberglass media to a secondsurface of a fiberglass media, then upward through upper compressionconveyor belt 10.

A first upper compression conveyor belt 10 with a specified traveldistance through the oven of at least fifteen feet and no more than onehundred feet in a first zone provides continuous contact of fiberglassmedia with heated air, which air is heated above three hundred degreesFahrenheit (300° F.) to no more than five hundred degrees Fahrenheit(500° F.). Temperature is held for a specified period of time necessaryto allow loft to begin to form with a second heated zone being 25degrees cooler at the lower end for final curing of the fiberglassmedia. The heating apparatus functions as both a loft control system anda curing apparatus for fiberglass and has been designed with twoextended length zones, a first heated zone and a second heated zone.This apparatus allows the use of urea formaldehyde or acrylic binderswith a minimal amount of additives (e.g. catalysts or buffers),minimizing variables and simplifying the process of producing qualityfiberglass media with better defined and more rigid skins. The additionof DEG (diethylene glycol) as an additive regulates moisture; however,it may only be added in a small percentage by weight. Additionally, thisprocess allows successful curing of unexpanded fiberglass mats with awider range of moisture levels. Ducting distributes heated air from aheated air distribution ducting below the bottom conveyor chain. Thiskeeps the bottom conveyor chain cleaner and precludes most particulatesfrom entering the exhaust stream, which keeps all the exhaust ductscleaner. The heating apparatus further saves energy by recirculatingeighty percent of the heated air in a first heated zone and ninety-fivepercent of the heated air in a second heated zone to maximize energyefficiency.

Synchronization of an upper compression conveyor belt 10 and a lowerconveyor chain 16 can be accomplished with separate direct drivescontrolled by an encoder. Encoders are utilized to maintainsynchronization even as belts stretch and components wear over time.Synchronization may further be maintained with an accumulator and awindup mechanism which are downstream of the heated apparatus. Both theaccumulator and the windup mechanism maintain proper tension on themedia throughout the process. The upper compression conveyor belt 10 isencased in a framework attached to lifting jacks 60 so that loft of thefiberglass media can be changed very quickly while media is still beingprocessed. The lifting jacks 60 respond very quickly and adjust topreset set points.

To provide for better maintenance and longer service life, apparatusroller outboard bearings 100 (shown in FIG. 9) on the ends of therollers 14 supporting the lower conveyor chain 16 have been relocated tothe exterior of the apparatus, away from the high heat load, so thatbearings can be lubricated while the heating and curing apparatus isprocessing fiberglass. The outboard bearings 100 are encased within aninsulation board 110, an enclosure that maintains the temperature of theheating apparatus while lubrication occurs.

The reduced heat exposure improves the life of the outboard bearings 100and extends the interval between required lubrications. A lubricationsystem for the drive chains on the upper compression conveyor belt 10lubricates the length of both drive chains, and having one on each sideof the conveyor belt minimizes downtime for chain lubrication. Furtheraccess panels are added to key locations all along the length of thefirst heated and second heated zones to facilitate maintenance ofcomponents and monitoring of processes.

Since other modifications and changes varied to fit particular operatingrequirements and environments will be apparent to those skilled in theart, the disclosed subject matter is not considered limited to theexamples chosen for purposes of disclosure, and covers all changes andmodifications which do not constitute departures from the true spiritand scope of this subject matter.

What is claimed is:
 1. An apparatus for processing fiberglass media, theapparatus comprising: an upper compression conveyor belt located in afirst heated zone, wherein air can flow through a surface of the uppercompression conveyor belt; an upper drive mechanism configured to drivethe upper compression conveyor belt; an upper tensioner configured tocontrol tension on the upper compression conveyor belt; a lower conveyorchain extending throughout and between the first heated zone and asecond heated zone adjacent to and downstream of the first heated zone,wherein air can flow through a surface of the lower conveyor chain; alower tensioner configured to control tension on the lower conveyorchain; a hot air distribution duct system extending beneath asubstantial length of the lower conveyor chain throughout the first andsecond heated zones and configured to supply heated air to updraft insequence through the lower conveyor chain, the fiberglass media, and theupper compression conveyor belt in the first heated zone and in sequencethrough the lower conveyer chain and the fiberglass media in the secondheated zone; and a return air plenum system extending above the uppercompression conveyor belt throughout the first heated zone and above thefiberglass media throughout the second heated zone and configured tocollect a substantial amount of the heated air, wherein the hot airdistribution duct system and the return air plenum system are configuredso that no substantial volume of air flows downward through the lowerconveyor chain in the first and second heated zones, wherein the uppercompression conveyor belt does not extend into the second heated zone,and wherein the upper compression conveyor belt and the lower conveyorchain are configured to compress the fiberglass media therebetween inthe first heated zone, with the lower conveyor chain configured tosubsequently carry the compressed fiberglass media through the secondheated zone.
 2. The apparatus of claim 1, further comprising a liftmechanism coupled to the upper compression conveyor belt.
 3. Theapparatus of claim 1, wherein: the hot air distribution duct systemcomprises a first hot air distribution duct configured to supply avolume of the heated air in the first heated zone and a second hot airdistribution duct configured to supply a volume of the heated air in thesecond heated zone, and the return air plenum system comprises a firstreturn air plenum configured to collect a substantial amount of thevolume of heated air in the first heated zone and a second return airplenum configured to collect a substantial amount of the volume ofheated air in the second heated zone.
 4. The apparatus of claim 3,further comprising: a first and second source of hot air fluidly coupledto the first and second hot air distribution ducts, respectively.
 5. Theapparatus of claim 4, wherein: the first and second sources of hot aircomprise first and second firebox assemblies for the first and secondheated zones, respectively, the first firebox assembly is fluidlycoupled to a downdraft duct, and the downdraft duct is fluidly coupledto the first hot air distribution duct.
 6. The apparatus of claim 5,wherein: the first firebox assembly recirculates 80% of the heated airfrom the first heated zone, the second firebox assembly recirculates 95%of the heated air from the second zone.
 7. The apparatus of claim 4,wherein the return air plenum system is fluidly coupled to the sourcesof hot air.
 8. The apparatus of claim 3, further comprising: a firstblower fluidly coupled to the first hot air distribution duct and to thefirst return air plenum; and a second blower fluidly coupled to thesecond hot air distribution duct and to the second return air plenum. 9.The apparatus of claim 1, further comprising: a fume hood; and a fumehood exhaust stack.
 10. The apparatus of claim 1, further comprising: anupper roller chain for the upper compression conveyor belt; and aplurality of lateral support devices coupled to the upper compressionconveyor belt and to the upper compression conveyor belt roller chain,wherein the plurality of lateral support devices are supported by asupport track.
 11. The apparatus of claim 1, further comprising: aninsulation board; and bearings coupled to the lower conveyor chain,wherein the bearings are positioned on a first side of the insulationboard and the lower conveyor chain is positioned on a second side of theinsulation board.
 12. The apparatus of claim 1, wherein: the firstheated zone is at a temperature of three hundred degrees Fahrenheit tofive hundred degrees Fahrenheit, the second heated zone is at atemperature of two hundred and seventy-five degrees Fahrenheit to fivehundred degrees Fahrenheit, and the temperature of the second heatedzone is at least twenty-five degrees lower than the temperature of thefirst heated zone.
 13. The apparatus of claim 1, wherein: the firstheated zone is between 15 feet and 100 feet in length, inclusive, andthe second heated zone is between 15 feet and 100 feet in length,inclusive.
 14. The apparatus of claim 1, wherein: the hot airdistribution duct extends beneath a substantial width of the lowerconveyor chain in the first heated zone; and the return air plenumextends above a substantial width of the upper compression conveyorbelt.
 15. The apparatus of claim 1, wherein: the first and second heatedzones are heated zones of a heating apparatus for curing the fiberglassmedia, and an exit of the second heated zone is an exit of the heatingapparatus.